package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import net.sf.jsqlparser.statement.select.KSQLWindow;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.TimeUnit;

/**
 * ClassName: SimpleRedisLock
 * Package: com.hmdp.utils
 * Description:
 *
 * @Author dhu-bion
 * @Create 2025/8/18 13:59
 * @Version 1.0
 */
public class SimpleRedisLock implements ILock{

    private StringRedisTemplate stringRedisTemplate;
    private String name;
    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;

    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    public SimpleRedisLock(StringRedisTemplate stringRedisTemplate, String name) {
        this.stringRedisTemplate = stringRedisTemplate;
        this.name = name;
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        //获取当前线程
        String threadId = ID_PREFIX + Thread.currentThread().getId();

        //获取锁
        Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);

        //防止自动拆箱空指针问题
        return Boolean.TRUE.equals(success);
    }


    //基于lua脚本实现解锁，保证分布式锁原子性，防止在判断key结束释放key开始之间阻塞，最终导致误删其他线程同一用户id的锁
    @Override
    public void unlock() {
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId());
    }


//    @Override
//    public void unlock() {
//
//        //获取线程标识
//        String threadId = ID_PREFIX + Thread.currentThread().getId();
//
//        //获取锁标识
//        String lockId = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
//
//        //对比标识是否一致
//        if(threadId.equals(lockId)){
//            //释放锁
//            stringRedisTemplate.delete(KEY_PREFIX + name);
//        }
//
//    }


}
